Abrus precatorius is an angiospermic plant grown all over India. It is commonly known as jequirity bean, rosary pea, crab’s eye or Indian liquorice. In hindi it is famous as gunchi or ratti.
Scientific classification of Abrus Precatorious
Abrus precatorius is a wild plant that grows best in dry regions at low elevations. It is a slender, perennial climber that twines around trees, shrubs, and hedges. Flowers are small and pale violet in colour with a short stalk, arranged in clusters.
The ovary has a marginal placentation. The fruit, which is a pod, is flat, oblong and truncate shaped with a sharp deflexed beak is about 3 to 4.5 cm long, 1.2 cm wide, and silky-textured. Each fruit contains 3-5 seeds which are about 0.85 cm long and 0.65 cm broad that weighs around 120mg.
The seeds are oval shaped, smooth and glossy textured and red coloured with black patch on one pole, which gives them a beautiful appearance.
The whole plant is poisonous and categorized as organic irritant poison. The most poisonous part of the plant is its seeds which contain the active principle called Abrin, which is a toxalbumin. The action of abrin resembles that of viperine snake bites.
Uses of Abrus Precatoroius
Though the abrus plant is poisonous, it has been in use for many centuries. Such as:
- The ratti seeds are used by tribal people as jewelery because of the beautiful and attractive colors and shape of seeds.
- In early India, the ratti seeds were used as a measure to weigh the gold, where 8 Ratti = 1 Masha; 12 Masha = 1 Tola (11.6 Grams). The seeds were used because they have consistent weight and remain unaffected from temperature and moisture due to the coating on seeds.
- The various plant parts are used for therapeutic purposes in Indian medicine, especially Siddha medicine. The oil extracted from the seeds is used as an aphrodisiac. The leaves are used to prepare tea which is helpful in curing fever, cough and cold.
- It is a famous arrow poison to kill the cattles used in early times by the kings to protect their hides. It is still used by the tribal and rural people in present time.
- Malingerers use abrus seed powder to produce conjunctivitis.
The powder of the seeds are mixed with spirit and water to form a paste which is then shaped into fine needles called Sui in hindi. The needles are about 15 mm long and weigh 90-120 mg. The dried and hardened sui’s are fitted in small holes made in a wooden stick, with which a blow is struck to the animal or human. This technique is used by the tribal or rural people.
Accidental poisoning is common among children, where they swallow or chew the seeds which are mistaken as something to eat.
Signs And Symptoms of Abrus Precatorious Poisoning
- In animals the punctured areas show local lesion, odema, necrosis and oozing of hemorrhagic fluid. The animal may feel drowsy and become apathetic. In further 2-3 days, the animal is unable to move or eat, drops down, and dies. Sometimes convulsions are also observed.
- In humans the poisoning shows dermatitis, conjunctivitis, asthma, rhinitis, etc.
- If the seeds are ingested, then severe gastroenteritis is observed with haemorrhagic abdominal pain, nausea, vomiting, diarrhoea, collapse and finally death.
- If the poison is injected via sui or needle, then the site of puncture shows swelling, ecchymosis and necrosis.
- Cardiac manifestations of viperian snake bite are shown such as cardiac arrhythmia. Vertigo, convulsions and cerebral edema are also common which may cause coma and death.
Fatal Dose & Period
Abrin is a supertoxic toxin which can cause death in 3-5 days with a dose of 1-2 seeds by ingestion or 90-120 mg via injection.
When the person dies due to abrin poisoning then the post mortem appearances shows following characteristics:
- The puncture site shows swelling and necrosis
- Fragments of needle/sui are found in the wound
- Haemorrhagic and congested internal organs
- Mucosal membranes, pericardium and peritoneum show petechial hemorrhagic patches.
If the victim is directed to the hospital within four hours of the poisoning then he/she can be treated.
- The first step for the treatment is dissecting the needles and decontamination of the wound.
- Gastric lavage or stomach wash is performed.
- Activated charcoal and purgatives are given to the victim so that he/she can vomit out all the poison from the stomach.
- An injection of Antiabrin is administered in the blood of the victim
- 10 percent of sodium bicarbonate is given intravenously to the victim which helps in maintaining the alkalinity of the urine and prevents the agglutination of red blood cells. It also prevents the blockage of renal tubules with hemoglobin G.
At the crime scene abrus seeds can be found which are indicative of abrin poisoning. The biological evidence may include vomit, saliva or feces.
Examination of Poison
Forensic analysis of abrus requires the extraction of poison from the biological evidence and chemical examination.
The poison is extracted by the Stas-Otto method and Modified Stas-Otto method.
The forensic examination Abrus precatorius includes the colour test, agglutination test and Thin Layer Chromatography.
The various colour tests performed for the identification of abrin are:
- Fast Blue B-Potassium Hydroxide Test: To the dried residue of the extract in a porcelain basin, a few drops of 5% ethanolic solution of Fast Blue B salt is added followed by 2 drops of aqueous KOH solution. A red to orange color is observed.
- Marquis Reagent: To the dried residue of extract, 2 drops of Marquis reagent (prepared by mixing 1 volume of formalin or formaldehyde solution with 9 volumes of concentrated sulfuric acid) is added. A pink color is formed.
- Van Urk Reagent: To the dried residue of the extract, one drop of Van Urk Reagent (prepared by dissolving 1 gm of p-amino benzaldehyde in 100 ml. ethanol and adding 10 ml. of hydrochloric acid). A green color changing to blue is observed.
- Agglutination test: Two drops of the aqueous solution of residue of the extract are added to 2 ml. of defibrinated blood (undiluted) in a small test tube. The red blood corpuscles agglutinate into a mass like that of sealing wax. It is a special test which is characteristic to Abrus precatorius.
- Thin Layer Chromatography: The TLC examination involves-
- Chloroform : Diethyl formamide : Ethanol :: 70 : 10 : 20.
- Iso-propanol : Chloroform : Methanol : Water :: 50:20:25:5.
Van Urk reagent which is prepared by dissolving 1 gm. of p-dimethylamino benzaldehyde in 100 ml. of ethanol and adding 10 ml. of hydrochloric acid.
Blue/ Bluish green/Greenish blue/yellowish brown/ yellow/brown.